Wednesday, September 25th, 2013 by Ryan Weyers
As warm air rises in a home it leaks out of the upper levels. New air must enter to replace the air that escaped. In fact, in an average home about half of the air in the home escapes each hour out of the upper levels. This creates a suction at the lower levels of the home to draw in replacement air. In older, leaky homes the air exchange rate can be as high as a full air exchange per hour.
What this "stack effect" does is create an airflow in your homes from bottom to top. So air from the basement is drawn upwards into the first floor, and then to the second floor. Of course it dilutes with other air in your homes, but building scientists say that up to 50 percent of the air you breathe on the first floor is air that came from the basement. If you have hot air heating with duct work, the air mixes even more thoroughly throughout the house.
Therefore, whatever is in your basement air is in your house and affecting you, whether you spend much time in the basement or not. If there is high humidity downstairs, there is higher humidity upstairs than there would be otherwise. If there is mold in the basement, there are mold spores upstairs. If there are damp odors downstairs - well you get the idea.